1. Field of the Invention
The invention relates to a switch, and more particularly to a rolling-ball switch that can form a closed or open circuit through a rolling movement of a ball member.
2. Description of the Related Art
Referring to FIG. 1, a conventional roiling-ball switch 100, as disclosed by the applicant in Taiwanese Patent No. I321798, includes a plastic housing 11, two metallic terminals 12, and two ball members 13. The plastic housing 11 has a surrounding wall 111 defining an axial hole 110, and two first engaging portions 112 provided respectively on two opposite open ends of the surrounding wall 111. The terminals 12 close the respective open ends of the surrounding wall 111, and have second engaging portions 121 engaged respectively to the first engaging portions 112.
In normal use, the ball members 13 are in contact with each other and with the respective terminals 12 to place the rolling-bail switch 100 in an ON state. When an external force is applied to the switch 100, the ball members 13 are moved away from each other to shift the switch 100 to an OFF state.
However, because the metallic terminals 12 may expand due to heat, in the ON state, although the second engaging portions 121 of the terminals 12 may be engaged to the first engaging portions 112 of the surrounding wall 11, the terminals 12 are likely to push the two opposite ends of the surrounding wall 12 outward. As a result, the terminals 12 are likely to be released from and moved out of the housing 11. Hence, the structure of the conventional rolling-ball switch 100 is unstable.